The process by which microorganisms bind to host cells is called adherence or adhesion, and it is now well accepted that this mechanism is an important step in the initiation of microbial colonization and infection. Generally, host cells possess structures ("receptors") that mediate binding of infectious microorganisms. Therefore, the receptors on host tissue are just as much a determinant of microbial infectivity as are the structures on microorganisms that mediate binding.
An example of a pathogenic microorganism of concern to humans is Chlamydia trachomatis. This microorganism is an obligate intracellular bacterial parasite of eucaryotic cells and is now known to be the most common sexually transmitted pathogen in industrialized societies (Moulder in Microbiology of Chlamydia, ed. A. L. Barron, pages 3-19, CRC Press, Boca Raton, Fla., 1988; Schachter in Microbiology of Chlamydia, pages 153-166, 1988). In the United States, it has been estimated that more than four million people contract chlamydial-related diseases each year (Eisner & Monahan, Diagnostics and Clin. Testing 28:26-28, 1990). Salpingitis, ectopic pregnancy, infertility, chronic pelvic pain, premature labor, neonatal conjunctivitis, infant pneumonia, endemic trachoma, urethritis, and epididymitis have all been directly or indirectly related to infection by the organism (Schachter 1988; Eisner & Monahan, 1990).
Another example of a pathogenic microorganism of concern to humans is Helicobacter pylori. This microorganism is an infectious agent of the human stomach. Infection is associated with both primary, chronic-active gastritis, and peptic ulcer disease (Blaser, J. Infect, Dis. 161:621-623, 1990; Marshall, J. Infect. Dis. 953:650-657, 1986; Marshall et al., Lancet ii:1437-1442, 1988). Each year there are more than 300,000 new cases, 3,200,000 recurrences, and 3,200 deaths from duodenal disease in North America (Schefler, Statistics for Health Professionals, 1984). One and one half percent of all worker absenteeism in North America is a result of peptic ulcers (Jansen, Am. J. Med. 81:42-48, 1986). Antral gastritis is associated in turn with gastrointestinal carcinoma (Johansenn and Sikjay, Acta Path. Microbiol. Scan. 85:240, 1977) and recent studies have linked H. pylori with GI cancer (Parsonnet et al., 30th Interscience Conference on Antimicrobial Agents and Chemotherapy, Atlanta, Ga., Oct. 21-24, 1990, abst. no. 5).
Due to the difficulties in current approaches to the prevention and treatment of microbial diseases, there is a need in the art for improved methods and compositions for preventing and treating microbial diseases. The present invention fills this need, and further provides other related advantages.